1. Field of the Invention
The present invention relates to apparatus and method for detecting an error status, and apparatus and method for recording information. More specifically, the present invention relates to the apparatus and the method for detecting the generation of the error at the time of recording main information to be recorded on an information recording medium or of reproducing the main information on the information recording medium.
2. Description of the Related Art
There are many conventional recording devices which records main information to be recorded on an information recording medium such as an optical disc as follows: the devices read address information recorded on the medium in advance. The address information indicates the recording position of the main information on the medium. Then the devices record the main information on the medium based on the address information.
Further, even at the time of reproducing the main information on the medium, the devices may read the address information at first. Then the devices search the main information on the medium based on the address information.
However, for example, at the time of recording the main information, the irradiated position by the light beam to be irradiated on the optical disc as the information recording medium is unexpectedly skipped from the position of the track to be correctly irradiated to a different position by reason of vibration and the like. This phenomenon is called a track skipping. If the track skipping is happened, the main information is recorded on the wrong position. Therefore another main information to be rightly recorded on the position is redundantly recorded.
If the main information is redundantly recorded, the reproduction of the information is incorrectly executed.
Therefore if the track skipping is happened, it is necessary to detect it immediately and to suspend reproducing and to restart recording on the right position.
In the conventional device, it is determined that the track skipping is happened when continuity of the address information is broken.
However, according to the conventional method of detecting the track skipping, it takes time to demodulate the address information and obtain information of the position to record.
Further, if the time to demodulate the address information and obtain the information of the position to record is longer than necessary time to record the amount of information corresponding to the maximum amount of information to be error-corrected at a time while the main information is reproduced, the main information is not correctly recorded as a unit of error correction. Therefore the error at the reproduction is not corrected, that leads to more serious problem.
It is therefore an object of the present invention to provide apparatus and method for detecting an error status, and apparatus and method for recording information which can promptly and accurately detect the error status, if the error status such as the track skipping and the like is happened at the time of recording or reproducing.
The above object of the present invention can be achieved by an apparatus for detecting an abnormal condition at the time of recording or reproducing information on information recording medium. The apparatus for detecting an abnormal condition at the time of recording or reproducing information on information recording medium is provided with: a detecting device for detecting control information to be detected every predetermined constant period in the information recording medium at least either at the time of recording or at the time of reproducing, the control information to control at least either the recording or the reproduction of the main information, and a determining device for determining that the abnormal condition occurs in either the recording or the reproduction, if no control information is detected every the predetermined constant period.
According to the apparatus for detecting an abnormal condition at the time of recording or reproducing information on information recording medium, the detecting device detects the control information to be detected every predetermined constant period in the information recording medium at least either at the time of recording or at the time of reproducing. The control information such as a pre-information is used for controlling at least either the recording or the reproduction of the main information. Then if no control information is detected every the predetermined constant period, the determining device determines that the abnormal condition occurs in either the recording or the reproduction.
Therefore the abnormal condition is promptly and accurately detected.
In one aspect of the apparatus for detecting the abnormal condition at the time of recording or reproducing information on information recording medium, said detecting device includes a generating device for generating a gate signal at the timing that the control information is to be detected in the information recording medium, and said determining device determines that the abnormal condition occurs if no control information is detected at the timing indicated by the gate signal.
According to this aspect, the apparatus can be simplified in its structure, and a presence or absence of the occurrence of the abnormal condition can be accurately detected.
In another aspect of the apparatus for detecting the abnormal condition at the time of recording or reproducing information on information recording medium, said determining device determines that the abnormal condition occurs if the probability that no control information is detected is higher than or equal to a predetermined threshold.
According to this aspect, an effect of a noise generated infrequently is eliminated and the presence or absence of the occurrence of the abnormal condition can be accurately detected.
In another aspect of the apparatus for detecting the abnormal condition at the time of recording or reproducing information on information recording medium, said determining device determines that the abnormal condition occurs if the probability that no control information is detected is higher than or equal to a predetermined threshold in a period to record or reproduce the amount of information corresponding to the maximum amount of information to be error-corrected at a time while the main information is reproduced.
According to this aspect, the abnormal condition can be detected soon, and an error correction at the time of reproduction is rightly executed.
In another aspect of the apparatus for detecting the abnormal condition at the time of recording or reproducing information on information recording medium, said information recording medium is an optical disc rotated at a constant linear velocity, and said control information is recorded every predetermined amount for the main information on the information recording medium in advance and includes at least address information indicating a recording position of the main information on the information recording medium.
According to this aspect, the presence or absence of the occurrence of the abnormal condition can be accurately detected.
In another aspect of the apparatus for detecting the abnormal condition at the time of recording or reproducing information on information recording medium, said abnormal condition is detected as a track skipping that a irradiated position by a light beam to be irradiated on an optical disc is unexpectedly skipped from a position of the track to be correctly irradiated to a different position.
According to this aspect, the presence or absence of the occurrence of the track skipping, which is likely to cause an abnormal of detection at the time of detecting the main information, can be accurately detected.
In another aspect of the apparatus for detecting the abnormal condition at the time of recording or reproducing information on information recording medium, said control information is used for controlling a recording of the main information on the information recording medium, and the apparatus further comprises a controlling device for controlling the recording of the main information on the information recording medium on the basis of the result of the determination by the determining device.
According to this aspect, the occurrence of the abnormal condition at the time of recording the main information can be promptly and accurately detected, and it is prevented that the recording of the main information is executed so that the abnormal condition occurs at the time of reproducing the main information.
The above object of the present invention can be achieved by method of detecting an abnormal condition at the time of recording or reproducing information on information recording medium. The method of detecting an abnormal condition at the time of recording or reproducing information on information recording medium is provided with: a detecting process of detecting control information to be detected every predetermined constant period in the information recording medium at least either at the time of recording or at the time of reproducing, the control information to control at least either the recording or the reproduction of the main information, and a determining process of determining that the abnormal condition occurs in either the recording or the reproduction, if no control information is detected every the predetermined constant period.
According to the method of detecting an abnormal condition at the time of recording or reproducing information on information recording medium, a detecting process detects control information to be detected every predetermined constant period in the information recording medium at least either at the time of recording or at the time of reproducing. The control information such as the pre-information is used for controlling at least either the recording or the reproduction of the main information. Then if no control information is detected every the predetermined constant period, a determining process determines that the abnormal condition occurs in either the recording or the reproduction.
Therefore the abnormal condition is promptly and accurately detected.
In one aspect of the method of detecting an abnormal condition at the time of recording or reproducing information on information recording medium, said detecting process includes a generating device for generating a gate signal at the timing that the control information is to be detected in the information recording medium, and said determining process determines that the abnormal condition occurs if no control information is detected at the timing indicated by the gate signal.
According to this aspect, the method can be simplified in its structure, and a presence or absence of the occurrence of the abnormal condition can be accurately detected.
In another aspect of the method of detecting an abnormal condition at the time of recording or reproducing information on information recording medium, said determining process determines that the abnormal condition occurs if the probability that no control information is detected is higher than or equal to a predetermined threshold.
According to this aspect, an effect of a noise generated infrequently is eliminated and the presence or absence of the occurrence of the abnormal condition can be accurately detected.
In another aspect of the method of detecting an abnormal condition at the time of recording or reproducing information on information recording medium, said determining process determines that the abnormal condition occurs if the probability that no control information is detected is higher than or equal to a predetermined threshold in a period to record or reproduce the amount of information corresponding to the maximum amount of information to be error-corrected at a time while the main information is reproduced.
According to this aspect, the abnormal condition can be detected soon. and an error correction at the time of reproduction is rightly executed.
In another aspect of the method of detecting an abnormal condition at the time of recording or reproducing information on information recording medium, said information recording medium is an optical disc rotated at a constant linear velocity, and said control information is recorded every predetermined amount for the main information on the information recording medium in advance and includes at least address information indicating a recording position of the main information on the information recording medium
According to this aspect, the presence or absence of the occurrence of the abnormal condition can be accurately detected.
In another aspect of the method of detecting an abnormal condition at the time of recording or reproducing information on information recording medium, said abnormal condition is detected as a track skipping that a irradiated position by a light beam to be irradiated on an optical disc is unexpectedly skipped from a position of the track to be correctly irradiated to a different position.
According to this aspect, the presence or absence of the occurrence of the track skipping, which is likely to cause an abnormal of detection at the time of detecting the main information, can be accurately detected.
In another aspect of the method of detecting an abnormal condition at the time of recording or reproducing information on information recording medium, said control information is used for controlling a recording of the main information on the information recording medium, and the method further comprises a controlling process of controlling the recording of the main information on the information recording medium on the basis of the result of the determination by the determining process.
According to this aspect, the occurrence of the abnormal condition at the time of recording the main information can be promptly and accurately detected, and it is prevented that the recording of the main information is executed so that the abnormal condition occurs at the time of reproducing the main information.